Negative psychosocial influences on cardiac activity in rats: the mediating role of the autonomic nervous system

Extensive research has shown that psychosocial factors such as chronic life stress, poor social support, depression, anxiety and hostility/Type A behavior represent important risk factors for the onset and progression of cardiac alterations. Putative pathophysiological mechanisms underlying these relationships include a dysregulation of the autonomic neural control of cardiac function. The autonomic nervous system represents the principal neural pathway through which the brain and the heart interact. The same cerebral regions (insular cortex, cingulate cortex, amygdala) involved in the regulation of emotions, mood and social behaviors, are also implicated in the autonomic control of cardiac function via hypothalamic and brain stem centers. Thus, the hypothesis of cardiac autonomic imbalance due to alterations in the brain-heart circuitry may provide a theoretical framework for a better understanding of the association between psychosocial risk factors and cardiac disease. The experiments presented in this thesis aim at investigating the role of autonomic mechanisms in mediating cardiac disturbances in rat models that reproduce human negative psychosocial conditions such as depression, anxiety and aggressiveness.